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Rayani K, Hantz ER, Haji-Ghassemi O, Li AY, Spuches AM, Van Petegem F, Solaro RJ, Lindert S, Tibbits GF. The effect of Mg 2+ on Ca 2+ binding to cardiac troponin C in hypertrophic cardiomyopathy associated TNNC1 variants. FEBS J 2022; 289:7446-7465. [PMID: 35838319 PMCID: PMC9836626 DOI: 10.1111/febs.16578] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 05/14/2022] [Accepted: 07/13/2022] [Indexed: 01/14/2023]
Abstract
Cardiac troponin C (cTnC) is the critical Ca2+ -sensing component of the troponin complex. Binding of Ca2+ to cTnC triggers a cascade of conformational changes within the myofilament that culminate in force production. Hypertrophic cardiomyopathy (HCM)-associated TNNC1 variants generally induce a greater degree and duration of Ca2+ binding, which may underly the hypertrophic phenotype. Regulation of contraction has long been thought to occur exclusively through Ca2+ binding to site II of cTnC. However, work by several groups including ours suggest that Mg2+ , which is several orders of magnitude more abundant in the cell than Ca2+ , may compete for binding to the same cTnC regulatory site. We previously used isothermal titration calorimetry (ITC) to demonstrate that physiological concentrations of Mg2+ may decrease site II Ca2+ -binding in both N-terminal and full-length cTnC. Here, we explore the binding of Ca2+ and Mg2+ to cTnC harbouring a series of TNNC1 variants thought to be causal in HCM. ITC and thermodynamic integration (TI) simulations show that A8V, L29Q and A31S elevate the affinity for both Ca2+ and Mg2+ . Further, L48Q, Q50R and C84Y that are adjacent to the EF hand binding motif of site II have a more significant effect on affinity and the thermodynamics of the binding interaction. To the best of our knowledge, this work is the first to explore the role of Mg2+ in modifying the Ca2+ affinity of cTnC mutations linked to HCM. Our results indicate a physiologically significant role for cellular Mg2+ both at baseline and when elevated on modifying the Ca2+ binding properties of cTnC and the subsequent conformational changes which precede cardiac contraction.
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Affiliation(s)
- Kaveh Rayani
- Molecular Cardiac Physiology Group, Simon Fraser University, Burnaby, Canada
| | - Eric R Hantz
- Department of Chemistry and Biochemistry, Ohio State University, Columbus, OH, USA
| | - Omid Haji-Ghassemi
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, Canada
| | - Alison Y Li
- Molecular Cardiac Physiology Group, Simon Fraser University, Burnaby, Canada
| | - Anne M Spuches
- Department of Chemistry, 300 Science and Technology, East Carolina University, Greenville, NC, USA
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, Canada
| | - R John Solaro
- Department of Physiology and Biophysics and the Center for Cardiovascular Research, College of Medicine, University of Illinois at Chicago, USA
| | - Steffen Lindert
- Department of Chemistry and Biochemistry, Ohio State University, Columbus, OH, USA
| | - Glen F Tibbits
- Molecular Cardiac Physiology Group, Simon Fraser University, Burnaby, Canada
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, Canada
- BC Children's Hospital Research Institute, Vancouver, Canada
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Matsuo T, Peters J. Sub-Nanosecond Dynamics of Pathologically Relevant Bio-Macromolecules Observed by Incoherent Neutron Scattering. LIFE (BASEL, SWITZERLAND) 2022; 12:life12081259. [PMID: 36013438 PMCID: PMC9410404 DOI: 10.3390/life12081259] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 08/09/2022] [Accepted: 08/12/2022] [Indexed: 01/22/2023]
Abstract
Incoherent neutron scattering (iNS) is one of the most powerful techniques to study the dynamical behavior of bio-macromolecules such as proteins and lipid molecules or whole cells. This technique has widely been used to elucidate the fundamental aspects of molecular motions that manifest in the bio-macromolecules in relation to their intrinsic molecular properties and biological functions. Furthermore, in the last decade, iNS studies focusing on a possible relationship between molecular dynamics and biological malfunctions, i.e., human diseases and disorders, have gained importance. In this review, we summarize recent iNS studies on pathologically relevant proteins and lipids and discuss how the findings are of importance to elucidate the molecular mechanisms of human diseases and disorders that each study targets. Since some diseases such as amyloidosis have become more relevant in the aging society, research in this field will continue to develop further and be more important in the current increasing trend for longevity worldwide.
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Affiliation(s)
- Tatsuhito Matsuo
- Institute for Quantum Life Science, National Institutes for Quantum Science and Technology, 2-4 Shirakata, Tokai 319-1106, Ibaraki, Japan
- Dept. of Physics, Univ. Grenoble Alpes, CNRS, LiPhy, 38000 Grenoble, France
- Institut Laue-Langevin, 71 Avenue des Martyrs, CEDEX 9, 38042 Grenoble, France
- Correspondence: (T.M.); (J.P.)
| | - Judith Peters
- Dept. of Physics, Univ. Grenoble Alpes, CNRS, LiPhy, 38000 Grenoble, France
- Institut Laue-Langevin, 71 Avenue des Martyrs, CEDEX 9, 38042 Grenoble, France
- Institut Universitaire de France, 75231 Paris, France
- Correspondence: (T.M.); (J.P.)
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Matsuo T, Arluison V, Wien F, Peters J. Structural Information on Bacterial Amyloid and Amyloid-DNA Complex Obtained by Small-Angle Neutron or X-Ray Scattering. Methods Mol Biol 2022; 2538:75-93. [PMID: 35951294 DOI: 10.1007/978-1-0716-2529-3_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Small-angle scattering is a powerful technique to obtain structural information on biomacromolecules in aqueous solution at the sub-nanometer and nanometer length scales. It provides the sizes and overall shapes of the scattering particles. While small-angle X-ray scattering (SAXS) has often been used for structural analysis of a single-component system, small-angle neutron scattering (SANS) has been used to reveal the internal organization of a multicomponent system such as protein-protein and protein-DNA complexes. This is due to the fact that the neutron scattering length is largely different between hydrogen and deuterium, and thus it allows to make a specific component in complexes "invisible" to neutrons by changing the H2O/D2O ratio in the solvent with or without molecular deuteration. In this chapter, we describe a method to characterize the biomolecular structures using SANS and SAXS, in particular, focusing on fibrillar proteins such as bacterial amyloids and their complexes with nucleic acids.
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Affiliation(s)
- Tatsuhito Matsuo
- Univ. Grenoble Alpes, CNRS, LiPhy, Grenoble, France.
- Institut Laue-Langevin, Grenoble Cedex 9, France.
- Institute for Quantum Life Science, National Institutes for Quantum Science and Technology, Tokai, Ibaraki, Japan.
| | - Véronique Arluison
- Laboratoire Léon Brillouin LLB, CEA, CNRS UMR 12, Université Paris Saclay, CEA Saclay, Gif-sur-Yvette, France
- Université de Paris Cité, Paris, France
| | - Frank Wien
- DISCO Beamline, Synchrotron SOLEIL, L'Orme des Merisiers Saint Aubin, Gif-sur-Yvette, France
| | - Judith Peters
- Univ. Grenoble Alpes, CNRS, LiPhy, Grenoble, France.
- Institut Laue-Langevin, Grenoble Cedex 9, France.
- Institut Universitaire de France, Paris, France.
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Mason AB, Lynn ML, Baldo AP, Deranek AE, Tardiff JC, Schwartz SD. Computational and biophysical determination of pathogenicity of variants of unknown significance in cardiac thin filament. JCI Insight 2021; 6:154350. [PMID: 34699384 PMCID: PMC8675185 DOI: 10.1172/jci.insight.154350] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 10/22/2021] [Indexed: 11/17/2022] Open
Abstract
Point mutations within sarcomeric proteins have been associated with altered function and cardiomyopathy development. Difficulties remain, however, in establishing the pathogenic potential of individual mutations, often limiting the use of genotype in management of affected families. To directly address this challenge, we utilized our all-atom computational model of the human full cardiac thin filament (CTF) to predict how sequence substitutions in CTF proteins might affect structure and dynamics on an atomistic level. Utilizing molecular dynamics calculations, we simulated 21 well-defined genetic pathogenic cardiac troponin T and tropomyosin variants to establish a baseline of pathogenic changes induced in computational observables. Computational results were verified via differential scanning calorimetry on a subset of variants to develop an experimental correlation. Calculations were performed on 9 independent variants of unknown significance (VUS), and results were compared with pathogenic variants to identify high-resolution pathogenic signatures. Results for VUS were compared with the baseline set to determine induced structural and dynamic changes, and potential variant reclassifications were proposed. This unbiased, high-resolution computational methodology can provide unique structural and dynamic information that can be incorporated into existing analyses to facilitate classification both for de novo variants and those where established approaches have provided conflicting information.
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Affiliation(s)
| | - Melissa L Lynn
- Department of Biomedical Engineering, University of Arizona, Tucson, Arizona, USA
| | | | - Andrea E Deranek
- Department of Biomedical Engineering, University of Arizona, Tucson, Arizona, USA
| | - Jil C Tardiff
- Department of Biomedical Engineering, University of Arizona, Tucson, Arizona, USA
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Yamaguchi M, Kimura M, Ohno T, Nakahara N, Akiyama N, Takemori S, Yagi N. Crossbridge Recruitment Capacity of Wild-Type and Hypertrophic Cardiomyopathy-Related Mutant Troponin-T Evaluated by X-ray Diffraction and Mechanical Study of Cardiac Skinned Fibers. Int J Mol Sci 2020; 21:ijms21103520. [PMID: 32429250 PMCID: PMC7278983 DOI: 10.3390/ijms21103520] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/10/2020] [Accepted: 05/11/2020] [Indexed: 12/02/2022] Open
Abstract
X-ray diffraction and tension measurement experiments were conducted on rat left ventricular skinned fibers with or without “troponin-T treatment,” which exchanges the endogenous troponin T/I/C complex with exogenous troponin-T. These experiments were performed to observe the structural changes in troponin-T within a fiber elicited by contractile crossbridge formation and investigate the abnormality of hypertrophic cardiomyopathy-related troponin-T mutants. The intensity of the troponin reflection at 1/38.5 nm−1 was decreased significantly by ATP addition after treatment with wild-type or mutant troponin-T, indicating that crossbridge formation affected the conformation of troponin-T. In experiments on cardiac fibers treated with the hypertrophic cardiomyopathy-related mutants E244D- and K247R-troponin-T, treatment with K247R-troponin-T did not recruit contracting actomyosin to a greater extent than wild-type-troponin-T, although a similar drop in the intensity of the troponin reflection occurred. Therefore, the conformational change in K247R-troponin-T was suggested to be unable to fully recruit actomyosin interaction, which may be the cause of cardiomyopathy.
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Affiliation(s)
- Maki Yamaguchi
- Department of Physiology, The Jikei University School of Medicine, Tokyo 105-8461, Japan; (N.N.); (S.T.)
- Correspondence: ; Tel.: +81-33433-1111
| | - Masako Kimura
- Department of Integrated Physiology, Kagawa Nutrition University, Saitama 350-0288, Japan;
| | - Tetsuo Ohno
- Department of Sports Medicine, Teikyo Heisei University, Chiba 290-0193, Japan;
| | - Naoya Nakahara
- Department of Physiology, The Jikei University School of Medicine, Tokyo 105-8461, Japan; (N.N.); (S.T.)
| | - Nobutake Akiyama
- Core Research Facilities for Basic Science, The Jikei University School of Medicine, Tokyo 105-8461, Japan;
| | - Shigeru Takemori
- Department of Physiology, The Jikei University School of Medicine, Tokyo 105-8461, Japan; (N.N.); (S.T.)
| | - Naoto Yagi
- Spectroscopy and Imaging Division, Japan Synchrotron Radiation Research Institute, SPring-8, Hyogo 679-5198, Japan;
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